1. Field of the Invention
The present invention relates to a fuel-injection device, and relates more particularly to mounting of the fuel-injection device.
2. Description of Related Art
A mounting device for mounting a fuel injector on an intake manifold is already known from German patent document DE 29 26 490 A1, according to which a mounting element axially fixes the fuel injector to the fuel rail or to a plug nipple, the mounting element being designed as a U-shaped securing clasp having two legs which are elastic in the radial direction. In the assembled state, the securing clasp engages in matching recesses of the plug nipple and is snapped into place in a recess in a connection piece of the fuel injector, the recess being designed as an annular groove. The axial clearance between the recesses and the securing clasp as well as between the annular groove and the securing clasp should be kept small, in order to achieve accurate fixation of the fuel injector without stresses on the gasket.
Particularly disadvantageous in the mounting device known from German patent document DE 29 26 490 A1 is the warping effect of the various mounting elements on the fuel injector. The flux of force generated in the fuel injector results in deformations and thus in lift changes of the valve needle and even in jamming, as well as in a compressive or bending load on the housing components, which usually have thin walls and are welded to one another at several points. Furthermore, any mounting measure, for example by a contact flange, leads to an increase in the radial expansion of the fuel injector and thus to higher space requirements in the installation.
A mounting device is already known from published German patent document DE 101 08 193 A1 for the two-way fastening of a fuel injector in a cylinder head of an internal combustion engine and of the fuel injector to a fuel rail. The mounting device includes a sleeve which is held between a shoulder of the fuel rail and a shoulder of the fuel injector, and is developed of an elastic material. In view of its tube-shaped structure, the sleeve is able to transfer the holding-down forces in an only conditionally effective manner to the fuel injector. The areas of the sleeve used as holding-down element, that are stressed by the shoulders of the fuel injector and the fuel rail, represent the cutting edges created during production of the blank of the sleeve conditioned by production.
One known design approach of a fuel-injection device, having a (high-pressure) fuel injector that is plugged into a connection piece of a fuel rail, and inserted into a receiving borehole of a cylinder head, in a so-called top feed construction, as well as having a known holding-down element, is described in published German patent document DE 10 2004 048 401 A1, to which reference will be made later in the description, in light of FIG. 1, for the better understanding of the present invention.
In addition, in the case of so-called bottom feed or side feed fuel injectors, other mounting possibilities of contact elements on fuel injectors are known. An electrically operated fuel injector valve is known from published European patent document EP 0 386 444 B1, which is able to be fastened by rotation about its longitudinal valve axis on a fuel distributor using a bayonet-type closure. The first electric contact elements of the fuel injector, that project from the valve housing parallel to the valve axis, are electrically contacted by second electrical contact elements which are situated on a contacting connector that is able to be placed onto the fuel rail in the direction of the valve's longitudinal axis.
The contacting connector that is able to be placed onto the fuel distributor is provided with threaded bores or spacer sleeves, in order to assure the fastening onto the fuel injector. The bayonet closure provided for fastening the fuel injector is developed with its bayonet locking bar directly on the fuel injector, and is in connection with recesses of the bayonet closure on the fuel distributor. This being the case, only fuel injectors are able to be inserted in the fuel distributor which have elements of the bayonet closure.
A fuel-injection device is known from published German patent document DE 43 29 774 A1, in which the side feed fuel injector has no functional elements for mounting in the valve seat of the fuel distributor. Instead, a rotatable holding-down clamp is used, which prevents the slipping of the fuel injector using an inner pressure element, and, using an outer fastening ring as a part of a bayonet closure, whose corresponding bayonet locking bars are developed on the fuel rail, for a simple and secure fastening on the fuel distributor.
The two abovementioned known design approaches, in this instance, have fuel distributors as large-volume fuel supply devices which take up and enclose the fuel injectors almost completely. The side feed fuel injectors, in this instance, have fuel flowing about them over a large surface and are supplied from the side with fuel. These construction types are suitable exclusively for intake manifold injection, but not for direct injection in which the fuel injectors are inserted directly into the receiving boreholes of the cylinder head.